Telephone system.



J. HARRISON.

TELEPHONE SYSTEM APPLICATION FILED JULY 29. 1910.

1,121,356, Patented Dec 15, 1914.

Abbash inventor:

Osxmmi damas Harrison JAMES HARRISON, OF GLENDALE, MISSOURI.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Dec. 15, 1914.

Application filed July 29, 1910. Serial No. 574,421.

To all whom it may concern Be it known that 1, JAMES HARRISON, a citizen of the United States of America, residing at Glendale, in the county of St. Louis and State of Missouri, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to a telephone system by which persons some distance away from a sub-telephone station may be signaled for the purpose of causing them to respond to a call from themain station. This system is particularly adapted for use in police service wherein it is very often desired to call a patrolman located in one of the police districts to a call box or sub-telephone station.

The object of my invention is to produce a very efiective signal, preferably an electric light, which is energized by passing an electric current of high voltage over the line wires of the telephone system and without extra line wires for carrying high voltage, provision being made whereby, when the high voltage is brought into service to operate the signal, it cannot in any way injure the various delicate parts of the telephone apparatus.

A further object is to provide a system f this description that permits of the operation of an annunciator or recording device through the same line wires also used for telephone service and signal service.

In the preferred form of my invention, a visual signal in the form of an electric lamp is connected to av transformer that is connected across the line wires at each sub-telephone station. The talking circuit and calling circuit are normally open at each telephone station, and therefore cannot be affected by a high tension of current transmitted over the line to operate the signal. To energize the signal, the operator at the main station moves a switch which disconnects the main station from the line wires and at the same time connects said wires to a source of electrical energy having a high voltage. This switch is preferably operated intermittently to cause the light to flash intermittently, and thus produce a very effective signal. Another object in operating the switch in this manner is to enable the person responding to the signal to notify the main station operator by closing the callingcircuit, the latter being disconnected from the main station while the lamp is energized.

In the accompanying drawing, which is a diagrammatical view of a telephone system embodying the features of my invention: A designates the main station, and B and C, respectively, designate sub-telephone stations connected to the main station by line wires 1 and 2. A switch D controlled by the main station operator is adapted to disconnect the line wires from the main station, and will be hereinafter more fully described. A switch plug having a sleeve 3 and a tip at constitutes the terminals of the cord circuit, and may be connected to the wires 1 and 2 at the main station, as shown by dotted lines. I do not deem it necessary to show the operators telephone, ringing and listening key, and other.

devices, included in the cord circuit, nor the means for connecting the cord circuit to another telephone line, as they are all wellknown parts of a main station and may be of any suitable construction. If desired, an operators telephone may also be connected to the terminals l and 2 leading to a switch adapted to connect said terminals to the wires 1 and 2*.

Each telephone station comprises a transmitter 5, a battery 6, and a talking coil 7, all connected together in a local circuit when the hook switch 8 is closed. The talking coil 9 and receiver 10 are connected to each other in series and may be connected across the line by closing the hook switch 8. A rotatable notched disk 11 is connected to the ground by a conductor 12 and resistance coil 13.

14E designates a spring contact connected to the line wire 2 and adapted to engage the periphery of the notched disk 11.

To call the main station operator, the person at the sub-telephone station rotates the disk 11 with the result of intermittently making and breaking a circuit leading to the central exchange, a definite number of times, depending on the number of notches in the disk 11. The. intermittent passage of current, as will be hereinafter described, energizes a signal such as a drop and a sounder at the main station, thereby notifying the operator that a sub-station is calling, and also indicating the number of the sub-station through the medium of the sig nal. The line wire 2 passes from the spring contact let to the switch D which connects it to a wire 2 leading to the spring jack 15 at the main station. The jack 15 normally connects the wire 2' to the wire 2 passing to a switch engaging the terminal of the conductor 16. This conductor 16 leads to a relay 17 and a battery 18, one pole of the latter being grounded at 19. As the notched disk 11 is also grounded, it will be understood that rotating said disk will intermittentlv energize a circuit including the relay 17. The conductor 16 is connected, at 20 to a bar 21 having its ends pivoted to the re lay armature 22 and 23. When the relay is energized, its armature 22 moves into engagement with the terminal of a Wire 2%, and thereby completes a circuit including the wire 24:, battery 18 and the drop annunciator 25, the battery and annunciator being connected to the ground. Energizing the relay 1? also causes its armature 23 to contact with the terminal of a wire 26 connected by a switch 27 to a wire 28, which leads to an indicator such as the sounder 29 or a recording device, may be used in lieu of said sounder. This connects the sounder to the battery, the circuit being completed through the ground, and causes the sounder to operate in response to the intermittent contacts made by the disk '11 andspring 14:. As the disks 11 at the various telephone stations have a different set of notches, the

operator can always tell by the operation.

of the sounder which telephone is calling.

3O designates a visual signaling device, preferably in the form of an electric lamp of high efiiciency. This lamp preferably requires a lower voltage than the source of supply, and is therefore connected to the secondary coil of the transformer 31 having its primary coil connected across the line Wires land 2. The source of energy herein shown for supplying the lamps 30 is an alternating current generator 32 connected to the switch contacts 33 by feed wires 3%. hen the switch D occupies the, position shown, the lines wires are connected to the main station, but it will be seen that by moving this switch to the right, it will disconnect the line wires from the main station and connect them to the generator 32. The generator 32 will then supply current to the signal lamps, and as the talking circuits are open at the sub-telephone stations, they will not be in any way afiected by this current. The current from the generator 32 cannot pass to the main station apparatus because the switch D is so constructed that it must disconnect the main station from the line wires before connecting said wires to the generator. Operating the switch D intermittently connects the line wires to the main station at intervals and enables the signaled person to answer the call by rotating the notched disk 11 and thus operate the drop 25 at the main station.

To prevent the sounder 29 from giving a false signal in the event that the disk 11 is operated during the intermittent move ment of the switch D, I prefer to disconnect said sounder by opening the switch 27 while the switch D is being operated.

The resistance coill3 arranged in the conductor 12 leading from the disk 11 to the ground is to prevent a free passage of the line wire current to the ground if the disk 11 is moved into engagement with the spring 1 while the generator 32 is energizing the line wires.

Any soundproducing signal, such as an ordinary polarized bell 35, may be arranged in a circuit leading from the primary coil on the transformer 31 to the ground, a condenser 36 being interposed between said bell and the transformer. This bell can also be used as a call signal and may be energized from the main station in any suitable manner; a

My invention is obviously capable of other embodiments than thatshown, and I desire in the annexed claims to cover all such modifications not falling without its generic spirit. For instance while the system is essentially a police call system, the combination of fire-alarm apparatus therewith (broadly specified as an alarm transmitting and receiving apparatus in the com binations claimed). it may be used also as a fire-alarm system.

I claim 1. In a telephone system, a main station including a sounder, an annunciator, and a switch for rendering the sounder effective; a telephone substation provided with a talking coil, and means for operating said sounder and annunciator comprising a normally open calling switch connected to the ground, and a resistance coil interposed be-. tween said calling switch and the ground; a pair of line wires connecting said substation to the main station, means for energizing said telephone system, a transformer having its primary coil connected across the line wires at the telephone substation, an electric lamp connected to the secondary coil of said transformer, a source of electrical energy of higher voltage than the telephone energizing means adapted to be connected to the line wires for energizing said lamp, and means operable for alternately connecting said source of electric energy and the main'station to said line wires. C

2. In a telephone system, a main station including a sounder, an annunciator, and a switch for rendering the sounder effective; a telephone substation provided with a talking coil, and means for operating said sounder and annunciator comprising a normally 'open calling switch connected to the ground, and a resistance coil interposed between said calling switch and the ground; a

pair of line wires connecting said substation to the main station, a source of current for the telephone at the substation, a transformer having its primary coils connected across the line wires at the telephone substation, an electric lamp connected to the secondary coil of said transformer, a source of electrical energy of higher voltage than the telephone current source, adapted to be connected to the line wires for energizing said lamp, and means adapted to disconnect the line from the main station and connect it to said high potential source, and for disconnecting said source and reconnecting the line to the main station, alternately, whereby the lamp at the telephone substation may be lighted at will, and the telephone service maintained uninterrupted at all other times.

3. In a telephone system, a central station containing substation line terminals, substations connected therewith and provided with the usual telephone equipment including ringing and talking circuits, a special signal at said substation unresponsive to ringing current, a line signal device at the central station normally connected with each substation line, a special device at the substation to operate said line signal, a special source of energy adapted to energize said special substation signal, switching means associated with said source of energy and adapted to disconnect the lines from their terminals and apply energy from said special source thereto independently of said terminals, a cord circuit to interconnect said line and from which ringing current may be applied thereto, together with an operators set separate from said cord cir- V cuit, and means for separately connecting said operators set to said line.

a. A sub-station signaling system comprising the usual sub-station equipment, line connections therefor, a transformer primary normally closed across said connections in multiple with said equipment, a transformer secondary including a special signal device responding to current through said transformer, and a special source of energy adapted to be connected with said line at a point distant from the said sub-station to energize said signal.

5. A substation signaling system comprising sub-station line connections, a transformer primary connected thereacross at the subscribers station, a transformer secondary including a special signal, a sub-station telephone apparatus comprising a normally open talking circuit connected across sald line in multiple with said transformer and a sub-station ringer connected between an intermediate point on said transformer primary and round, together with a special source of energy at a distant point adapted to be connected to said subscribers line to energize said special signal.

6. A sub-station signaling system comprising an all-metallic substation line circuit, a transformer primary connected across said circuit at the sub-station, a transformer secondary including a special signal responsive to current through said transformer, a substation telephone apparatus comprising a normally open talking circuit connected across said line in multiple with said transformer and a sub-station ringer connected between an'intermediate point on said transformer and ground, and a special source of energy located at a distant point and adapted to be connected to said line to supply current to said transformer and energize said special signal.

7. A sub-station signaling system com,- prising an all-metallic sub-station line circuit, a transformer primary connected across said circuit at the sub-station, a transformer secondary including a special sig nal responsive to current through said transformer, a sub-station telephone apparatus comprising a normally open talking circuit connected across said line in multiple with said transformer and a substation ringer connected between an intermediate point on said transformer and ground, an alarm signal transmitter at the substation connected between one side of said circuit and ground independently of said transformer, and a special source of energy located at a distant point and adapted to be connected with said line to supply current to said transformer to energize said special signal, together with a receiving device normally connected with said line at the said distant point and adapted to receive signals sent by said transmitter.

8. A sub-station signaling system comprising sub-station line connections, a transformer at the sub-station having its primary across said connections and a special signal across its secondary winding, a sub-station ringer connected between a mid-point of said primary winding and ground, and a source of energy at a distant point adapted to be connected with said line to apply special signaling current over the line to said transformer to energize said signal, said substation ringer being responsive to current from an independent source applied over either or both sides of the line and ground or common return.

9. In a combined sub-station signaling and police signal system, a central station, a sub-station, and an all-metallic line circuit between said stations, a transformer at the sub-station having primary and secondary windings, said primary winding being connected across said line and said secondary winding including a special signal, said sub-station including a normally open talking circuit connected directly acrossrsaid line in multiple with the primary of said transformer and a sub-station ringer connected between a midpoint on said transformerwinding and ground, a special signal transmitter connected between one side of said line circuit and ground, a special signal receiving apparatus at the central station, a special operators set, a plug operated spring contact switch and a special key associated with said operators set and through which connection is normally made from said line to said special signal receiving apparatus, operators cord circuits through which talking connection may be made with other lines and from which the substation may be rung up in the usual manner, a special source of energy adapted to energize said transformer and operate said special sub-station signal, and switching means adapted to break the line connection with said main station apparatus and connect said special source of energy thereto independently thereof.

JAMES HARRISON. In the presence of E. B. LINN, A. J. MOCAULEY.

Copies of this patent may be obtained for fiv'e cents each, by addressing the Commissioner of Patents, Washington, D. C. 

